Steven A. Hughes. Ph.D., P.E. Coastal and Hydraulics Laboratory US Army Engineer Research and Development Center David R. Basco. Ph.D., P.E. Coastal Engineering Center Old Dominion University
Overview of Wave Runup and Overtopping Overview of Wave Reflection and Transmission Example Problems Based on: CEM Chapter VI-5-2 (Author: Hans F. Burcharth) CEM Chapter VI-7 (Author: David R. Basco)
Wave Runup: Vertical distance between SWL and maximum water elevation Wave Rundown: Vertical distance between SWL and minimum water elevation Important: Wave runup determines structure crest elevation for minimal overtopping condition
Smooth Impermeable Slopes
Smooth Impermeable Slopes
Smooth Impermeable Slopes
Smooth Impermeable Slopes Alternate Formulation
Additional Factors γ r - Influence of surface roughness γ b - Influence of fronting berm γ h - Influence of shallow water γ β - Influence of approaching wave angle
Impermeable Rock Slopes Coefficients Permeable Rock Slopes
The Surf-Similarity Parameter Runup No Overtopping-Impermeable Smooth Rough Partial-Safety Factors Statistical Distribution No Overtopping-Permeable Overtopping Average Discharge Rate Summary CEM-vs-SPM
SUMMARY: WAVE RUNUP 1. Significant Wave Runup, R us Both SPM (1984) and CEM (2000) give similar results CEM (2000) methods easy for EXCEL 2. Prevent overtopping - Statistical distributions Ru2% 2% based on actual, large-scale tests, irregular waves Estimates of Rui% % based on Rayleigh distribution are incorrect
SUMMARY: WAVE RUNUP 3. Permeable Breakwaters Little data in SPM (1984) Core permeability significantly influences results Methods now available in CEM (2000) Use CEM (2000) methods to estimate wave runup
Definition of freeboard Wave Overtopping... Occurs where the highest runup levels exceed the freeboard Unevenly distributed in space and time Usually expressed as time-averaged overtopping discharge Discharge from a single wave can be 100 times average
Critical Average Overtopping Discharges
Generally expressed in the form...
Typical CEM Table (one of six)
SUMMARY: WAVE OVERTOPPING 1. Average wave overtopping rate Both SPM (1984) and CEM (2000) give similar results CEM (2000) methods easy for EXCEL 2. Critical values for traffic and structural safety SPM (1984) gives no information CEM (2000) gives critical values to justify raising crest elevation
SUMMARY: WAVE OVERTOPPING 3. Volume estimates for individual waves CEM (2000) gives methods Use CEM (2000) methods to estimate wave overtopping
Overview of Wave Runup and Overtopping Overview of Wave Reflection and Transmission Example Problems Based on: CEM Chapter VI-5-2 (Author: Hans F. Burcharth) CEM Chapter VI-7 (Author: David R. Basco)
Bulk Reflection Coefficient
Seelig Equation Structure a b With
Six other cases are given
Transmission Coefficient Coastal Engineering Practice Committee
Conventional Low-crested Reef breakwaters Van der Meer and d Angremond (1991)
Overview of Wave Runup and Overtopping Overview of Wave Reflection and Transmission Example Problems Based on: CEM Chapter VI-5-2 (Author: Hans F. Burcharth) CEM Chapter VI-7 (Author: David R. Basco)
Figure V-3-6 Virginia Beach seawall/boardwalk (a) artist s perspective (b) aerial photo, 1997 (courtesy of Virginia Beach, VA)